A half-century scientific quest culminated early Wednesday as physicists announced the discovery of a new subatomic particle — one theorized to be so fundamental that without it, nothing could exist.

Dubbed the Higgs boson — or the “God particle,” to the chagrin of scientists — the particle is thought to create a sort of force field that permeates the universe, imbuing everything that we can see and touch with the fundamental property known as mass.

“As a layman I now say, I think we have it,” Rolf-Dieter Heuer, director general of CERN, the European Organization for Nuclear Research, said immediately after physicists presented compelling evidence of the new particle at a seminar in Geneva.

“Do you agree?” he asked the several hundred scientists packing CERN’s main auditorium.

Applause broke out. The video feed from CERN showed Peter Higgs, the University of Edinburgh physicist who theorized the existence of this exotic particle in 1964, tearing up.

“We have a discovery,” said Heuer. “We have discovered a new particle consistent with the Higgs boson. It’s a historic milestone today.”

While there were typical scientist-esque notes of caution — a CERN statement called the discovery “preliminary” — scientists around the world celebrated the moment.

A video feed from Melbourne, Australia, where an international physics conference is set to begin, showed an auditorium packed with cheering scientists.

“One of the most exciting weeks of my life,” said Joe Lykken, a theoretical physicist who worked on one of the two CERN experiments that found evidence of the new particle.

At Fermilab, longtime home of the U.S. high-energy physics community, some 300 people stuffed into two rooms to watch a video feed from Geneva, said Don Lincoln, a Fermilab physicist who contributed to the CERN experiments.

“It’s incredible,” said Lincoln. “People were riveted. Discovery is what scientists live for.”

At Columbia University in New York, 75 people shared a bottle of champagne brought by experimental physicist Michael Tuts, one of the more than 6,000 scientists who contributed to the discovery.

“I’m still astonished that at 3 a.m. on the Fourth of July you can gather” so many people excited about the arcane field of subatomic physics, Tuts said. High school students, undergraduates, graduate students and professors all shared the bubbly after the discovery became clear.

With a self-imposed deadline of July 4 — set two years ago to line up with the conference in Melbourne — CERN physicists raced in recent days to collect and analyze enough data to say they had, indeed, found a new particle that looked like the long-sought Higgs.

As late as Tuesday, two teams pored over results from the last run of high-energy subatomic collisions at the huge Large Hadron Collider straddling the French-Swiss border.

“It’s the last month of running that did it,” Joe Incandela, spokesman for one of the two experiments at CERN that found evidence of the Higgs, said during his presentation Wednesday morning.

The discovery of the new particle completes what’s known as the Standard Model of particle physics, the equivalent of chemistry’s Periodic Table. The Standard Model lists and arranges the particles and forces of nature. Many of the particles were predicted long before they were found — the Higgs was the last holdout, and the most important.

That’s because it is thought to give rise to the “Higgs field,” a sort of force field that permeates everything.

“We know the Higgs is at the center of everything,” said Lykken. “This is why (Nobel Prize-winning physicist) Leon Lederman called it the God particle. It talks to all the other particles in some fundamental way.”

When the other particles that make up the stuff of the universe — protons, neutrons, electrons and so on — interact with the Higgs field, they acquire the trait known as mass.

One way to think of the Higgs field: It’s the water the entire universe swims in.

The CERN physicists did not see this new particle directly, because it disintegrates too quickly. Rather, they divined its existence from sifting through the debris of millions of high-energy subatomic collisions and then searching for clues that the Higgs had been there. It’s like divining the presence of an elusive snow leopard by studying thousands of criss-crossed paw prints.

But by studying these traces, the CERN physicists saw a “bump” in their data consistent with a Higgs boson.

Two independent teams, working on two separate particle detectors, arrived at similar results — a kind of cross-check. The two teams, each with more than 3,000 scientists, were not to share their results with each other before the seminar Wednesday at CERN.

The idea of the Higgs, or something like it, has been around since 1964, when it was first hypothesized by Peter Higgs. The Standard Model of physics had a hole in it — one that needed to be filled by a particle that imbues everything with mass. It became known as the Higgs boson — and its discovery, many scientists say, will now surely garner a Nobel Prize.